Time-resolved immunofluorometry and other frequently used immunoassay types for follicle-stimulating hormone compared by using identical monoclonal antibodies
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Published on: December 12, 2011
S Madersbacher1, T Shu-Chen, S Schwarz
1Institute for Biomedical Aging Research, Austrian Academy of Sciences, Innsbruck.
Insights
The time-resolved immunofluorometric assay (IFMA) offers superior sensitivity and a wider measuring range for human follicle-stimulating hormone (hFSH) detection compared to other immunoassay methods. This makes IFMA a reliable and efficient tool for hFSH analysis across all age groups.
Area of Science:
- Biochemistry
- Immunology
- Analytical Chemistry
Background:
- Accurate quantification of human follicle-stimulating hormone (hFSH) is crucial for diagnosing various endocrine disorders.
- Different immunoassay formats exist, each with unique performance characteristics that can impact diagnostic utility.
Purpose of the Study:
- To compare the performance of four different immunoassay methods for hFSH quantification.
- To evaluate the influence of assay design and quantification system on assay performance using the same monoclonal antibodies (MCA).
Main Methods:
- Development and optimization of a time-resolved immunofluorometric assay (IFMA), immunoenzymometric assay (IEMA), immunoradiometric assay (IRMA), and competitive radioimmunoassay (RIA).
- Utilized the same monoclonal antibodies (MCA) against hFSH for all assay formats.
- Assessed assay sensitivity, measuring range, signal-to-noise ratio, and sample analysis across a broad age spectrum.
Main Results:
- IFMA demonstrated the lowest detection limit (2 ng/L), widest measuring range (2-160,000 ng/L), and highest signal-to-noise ratio (13,000:1).
- 100% of serum samples from 200 individuals (ages 2-91 years) were within the IFMA measuring range.
- Conventional IEMA and RIA showed significantly lower percentages of samples within their respective measuring ranges (32% and 8%).
Conclusions:
- IFMA exhibits superior sensitivity and assay range compared to IRMA, IEMA, and RIA for hFSH determination.
- The IFMA format allows for reliable, cost-effective, and time-efficient hFSH measurement in individuals from infancy to senescence.
- Assay design significantly influences performance, with IFMA proving advantageous for comprehensive hFSH analysis.
Abstract:
The influence of assay design and quantification system on assay performance was investigated by developing, optimizing, and comparing a time-resolved immunofluorometric assay (IFMA), an immunoenzymometric assay (IEMA), an immunoradiometric assay (IRMA), and a competitive radioimmunoassay (RIA), all performed with the same monoclonal antibodies (MCA) directed against human follicle-stimulating hormone (hFSH). The lowest detection limit (2 ng/L for hFSH-I-3, corresponding to 2.5 mIU of 1st International Reference Preparation of hFSH 78/549 per liter), the widest measuring range (2-160,000 ng/L), and the greatest signal-to-noise ratio (13,000:1 at 160,000 ng/L) were obtained in the IFMA. For analysis of serum samples from 101 male (ages 2-91 years) and 99 female (ages 2-90 years) individuals at a single dilution, 100% of samples were within the measuring range of the IFMA, whereas only 87%, 55%, 32%, and 8% of the sera were for the IRMA, the IEMA evaluated with double-wavelength measurement, the conventional IEMA, and the competitive MCA-based RIA, respectively. These studies demonstrate clear advantages of the IFMA in sensitivity and assay range, which allows reliable and cost- and time-effective determination of hFSH in individuals from infancy to senescence.
